Passive Cavity Vortex Flow for Fanless Heat Transfer

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Solution Overview

Problem

Conventional thermal management systems rely on mechanically driven devices like fans and pumps to manage waste heat, which require additional energy and are not efficient in creating a passive flow for heat transfer.

Innovation Solution

A passive vortex is induced using a cavity with varying thermal conductivity surfaces to create a horizontal convective flow, enhancing heat transfer without moving parts by leveraging temperature differences across the cavity walls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If mechanically driven devices (fans and pumps) are used to force conductive fluid past the conductive surface, then heat transfer is achieved, but additional electrical or combustive activity is required

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidelectrical or combustive energy consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent replaces mechanical driven devices (fans and pumps) with a passive vortex system that uses thermal energy to generate fluid flow. The vortex is created by heating one side of a cavity while keeping the other side cooler, which generates natural convection currents that spiral around the cavity and exit through the top, eliminating the need for mechanical components and electrical/combustive energy input

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the waste heat itself to drive the cooling process. The temperature difference between the heated and cooled sides of the cavity automatically generates the convective flow, making the system self-sustaining without requiring external energy input beyond the waste heat being dissipated

Inventive Principle:

Principle #25Self-service

2Device complexity

If passive vortex is formed using temperature difference across cavity, then mechanical devices are eliminated, but cavity structure with varying thermal conductivity is required

Engineering Contradiction:

Improveelimination of mechanical componentsVSAvoidcavity structure fabrication

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The cavity is designed with non-uniform thermal conductivity properties - one side of the cavity is made of material with higher thermal conductivity while the other side uses material with lower thermal conductivity. This local variation in thermal properties creates the necessary temperature difference to drive the passive vortex, and can be achieved through selective coating, composite materials, or multi-layer construction

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The passive vortex system effectively enhances heat transfer by creating a stable, horizontal flow that can be used for cooling or heating applications, reducing the need for mechanical devices and improving efficiency.

Implementation Method 1

A passive vortex formed or induced from a temperature difference across a cavity or void aggregates and supports a horizontal flow over the top of the cavity

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

A passive vortex formed or induced from a temperature difference across a cavity or void aggregates and supports a horizontal flow

Methodology Applied

Scientific EffectVortex: Vortex Ring

Implementation Method 3

an interconnection of surfaces varying in thermal conductivity or temperature is arranged in the path of a fan or convection flow for initiating a passive vortex

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12460882B2Passive flow control for captive vortex

Publication Date: 2025.11.04 WORCESTER POLYTECHNIC INSTITUTE

AI summary

A passive vortex formed or induced from a temperature difference across a cavity or void aggregates and supports a horizontal flow over the top of the cavity. A cavity of a suitable depth and width exhibits a small difference in temperature, or heat source, along the sides or bottom of cavity. A resulting convective flow tends to form a rising current along a warmer side, and a complementary downward current on an opposed side of the cavity. The formed vortex tends to draw the cooler downward flow across the warmer, heated surface, enhancing the vortex flow. The vortex aligns with a horizontal flow across the top of the cavity as the upward current complements the downward current on an opposed side of the cavity. A plurality of adjacent cavities tend to align with an aggregate horizontal flow contributed from each cavity.